Steam-turbine.



C. E. SEARCH & H. C. WRIGHT.

STEAM TURBINE. APPLICATION FILED AUG.26. 1914.

Patented June 13, 1916.

WCom may tinrrnn snares PATENT chines. I

CHARLES EDWIN SEARCH AND ROBERT C. WRIGHT OF MILWAUKEE, WISCONSIN, ASSIGNORS TO ALLIS-CI-LALMERS MANUFACTURING COMPANY, OF MILWAUKEE,

WISCONSIN, A CORPORATION OF DELAWARE.

STEAM-TURBINE.

Specification of Letters Patent.

Patented; June 13, 1916.:

Original application filed February 9, 1914, Seria1 No. 818,155. Divided and this application filed August 26,1914. Serial No. 559,119.

- Wisconsin, have invented a certain new and useful Improvement in Steam-Turbines, of which the following is a specification.

This invention relates to steam turbines and more particularly to means for securing the shroud to the blade ends and for properly positioning the blades atone end.

' An object of the invention is to provide a blade structure for steam turbines which is simple in construction, eflicient in operation, and which possesses the requisite amount of rigidity and strength, especially to with-' stand vibration.

One of the more specific objects of the invention is to provide a very light shroud having means in the form of a recessed longitudinal corrugation or projection for properly positioning the blade ends, the shroud being secured to the blade by fusion of metal.

This application is a'division of applicationSerial No. 818,155, filed February 9,

- 1914, claiming a process of manufacturing the article claimed herein. The article of manufacture disclosed herein is covered broadly by claims of application Serial No. 856,983, filed Aug. 15, 1915.

Heretoforeit has been proposed to fasten a shroud to blade ends by means of tenons formed on the blade ends and passing through holes in the shroud, the tenons being riveted over the shroud stock. It has also been proposed to fasten a light corrugated shroud to the ends of blades by fusion of metal, for instance by brazing, the blade ends having been properl positioned by forming tenons on the bla es and inserting the same in holes formed in the shroud. An objection to these constructions is that considerable blade stock is wasted in forming the tenons on the blades, this objection being eliminated in the present invention, wherein blades'having single-surfaced ends may be utilized.

The expression single-surfaced end as used herein is intended to apply to a blade end which is free of any pro ection or recess ,abruptly interrupting the continuity of the end surface of the blade. The expression therefore includes blade ends having surfaces which are either'plane or curved, these surfaces being. either perpendicular or oblique relative to the edges of the blades.

'A clear conception of an embodiment of the invention may be had by referring to the drawing accompanying and forming a part of this specification, in which like reference characters designate the same or similar parts in the various views.

, Figure 1 is a plan view of'a fragment of a shroud attached to a plurality of blades.

Fig. 2 is an elevation of a fragment of a shroud attached to a plurality of blade fragments. Fig. 8 is a transverse section through a plurality of blades having a fragment of a shroud attached thereto, the section being taken along the line III-III of Fig. 2. looking'in the direction of the arrows. Fig. 4 is a transverse vertical section through a shroud attached to a fragment of a blade showing also a fragment of the stationary turbine casing, the section being taken along the line IV-IV of Fig. Fig. 5 is a transverse vertical section through a shroud attached to a fragment of a blade showing also a fragment of a stationary turbine casing, the section being taken along the line VV of Fig. 3. v

While the figures of the drawing disclose rotor or movable blading of a turbine of the parallelflow type, it is to be understood that the invention is equally applicable to stator or. stationary blading, as wellas to other types of turbines. The shroud 2 is made very light and is provided with a longitudinal corrugation or projection 7 having a continuous depression on the opposite side thereof. This corrugation or projection 7 forms a longitudinal arch which serves to strengthen or stiffen the shroud. The depression on the opposite side of the projection 7 is of such extent that the thickness of the projection 7 is substantially equal to loo .chining of the shroud so as to bring the proximity to the stationarycontinuous projection '7 is in fact altered to form divisional projections by the formation of the recesses &. The recesses 4: are properly directed so as to permit application of the shroud 2 to'the single-surfaced ends of the blades 1, these blade ends being centrifugal force.

properly positioned by the side walls of the recesses. The shroud 2 is applied to the ends of the blades 1 at the recesses, transverse derangement of a blade from the row'of blades being temporarily prevented by any suitable retaining means, not shown. The shroud 2 and blades 1 are then united by fusion of metal by soldering, brazing, welding or any other suitable method. In the drawing the shroud has been united along its base with the single-surfaced ends 5 of the blades 1.

Uniting the blades 1 and shroud 2 by fusion ofmetal produces a unitary structure of great rigidity and strength especially to withstand vibration. This construction permits the use of a very light shroud 2 instead of a comparatively heavy shroud, such as was of necessity used when the shroud was secured to the blade ends by riveting tenons at the ends of the blades which had previously been passed through openings in the shroud. In, this prior construction the shroud was secured to the .blade only at the punched portion, thus necessitating the formation of the remaining portion of the shroud of considerable strength, that is thickness, in order to withstand the strains to which the shroud was subjected due to In the construction of the present invention the blade 'is united with the shroud along substantially its entire end by fusion of metal, thus permitting use of a comparatively light shroud. The fact that the shroud 2 of the'present invention is corrugated at its blades, by the formation 0 the projection 7 thereon, also .adds rigidity to the completed integral structure in addition to that gained by uniting the sh portions between road 2 and blades -1 by fusion of metal. The formation of a continuous depression opposite the projection 7 furthermore permits the production of a very light shroud which is circumferentially free from projections or paddles such as are produced by the riveted-over-tenon ends of the construction of the prior art above referred to. The formation of the blades with single-surfaced .ends furthermore eliminates the waste of blade stock, resulting in the construction of tenoned blades. I

It should be understood that it is not desired to be limited to the exact details of construction shown and described except as required by the scope .of the appended claims, for obvious modifications Wlll occur to a person skilled in the art.

It is claimed and desired to secure by Letters Patent,-

1'. In combination, a blade, and a shroud having a recessed longitudinal corrugation for positioning said blade, said shroud being secured to said blade at said recess; I

2'. In combination, a blade, and a shroud having a recessed longitudinal corrugation for positioning said blade, said shroud being secured to said blade at said recess by fusion'of metal.

3. In combination, a plurality of blades, and a shroudhaving a portion forming a recessed longitudinal arch for positioning said blades, said shroud being secured to said blades at said recesses.

4. In combination, a plurality of blades, and a shroud having a portion forming a recessedlongitudinal arch for positioning said blades, said shroud being-secured to said blades at said recesses by fusion of metal.

.5. In combination, a plurality of blades,

and a shroud having arecessed longitudinal projection and a depression opposite said projection whereby said shroud is of substantially the .same thickness throughout,

said shroud being secured to said blades at said recesses.

6. In combination, a plurality of blades, and a shroud having a portion forming a recessed longitudinal arch, said blades and said shroud being united by fusion of metal.

In testimony whereof, the signatures of the inventors are aflixed hereto in the presonce of two witnesses. i

' C. EDWIN SEARCH.

. ROBERT C. WRIGHT. l Witnesses:

- F.- L. TENNEY, W. H. LIEBER. 

